The present invention relates to a precursor of prostaglandins, 10-substituted-5,9-dioxatricyclo-[6.4.0.0..sup.2,6 ]dodecane-4-one, which is a new compound and useful as an intermediate for production of prostaglandins, and process for production thereof.
Prostaglandins (referred to as PGs hereinafter) are a general name of a compound having a basic skeleton represented by the formula: ##STR1## which are found in, for instance, tissues, organs, metabolites of humans and animals. PGs have lately attracted considerable attention as various kinds of medicament because of their great variety of physiological activities. Recently, it has been tried to develop new PGs and their derivatives exhibiting a specific activity to a pathological condition to be controlled with less or without side effects. We have studied synthesis and pharmacological activities of PGs in which the 13- and 14-position are saturated and the carbon atom of the 15-position forms carbonyl group, that is, 13,14-dihydro-15-keto-PGs, and found that they exhibit specific activity in comparison with natural PGs (Japanese patent application Nos. 18326/1988, 108329/1988 etc.).
According to a typical and conventional process for producing PG derivatives, at least three processes are indispensably applied to introduce a protective group for the carbonyl group in the .omega.-chain before the .alpha.-chain is introduced into the compound (4) derived from Corey lactone as shown in the synthetic chart.